System and method of forming a protective covering for a wire harness

ABSTRACT

A motion-powered liquid sprayer that can increase the number of rotations of the pump relative to each rotation of the wheel or axle is provided. The sprayer can include a gearing assembly that employs gears to increase the number of pump revolutions as a function of the wheel or axle rotation. The sprayer can also include a gear pump that employs an over-capacity or enhanced gullet together with blow-by spacing to control consistent liquid flow relative to variable motional velocities. Further, the sprayer can include a vertically adjustable nozzle as well as a free reverse rotation wheel hub.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Continuation of pending U.S. patent applicationSer. No. 12/055,070 entitled “SYSTEM AND METHOD OF FORMING A PROTECTIVECOVERING FOR A WIRE HARNESS” and filed Mar. 25, 2008. The entirety ofthe above-noted application is incorporated by reference herein.

FIELD OF INVENTION

This invention relates to a system and method for forming a protectivecovering for a wire harness, and more particularly, to a system andmethod for forming a protective covering on a wire harness for use ininterconnecting electrical systems.

BACKGROUND

The electrical systems of vehicles, such as automobiles and commercialvehicles, are intricate and continue to develop as manufacturers seek toprovide more and more electrical capabilities to consumers. Early modelsof such vehicles had relatively few electrical systems, and many ofthese systems were relatively simple by today's standards. In contrast,modern electrical systems often involve numerous and complex subsystems,requiring substantial use of conductors and electronic devices forinterconnecting components of the electrical systems.

As the demands on electrical systems have proliferated, manufacturershave sought to control the space occupied by conductors used in theelectrical systems by bundling these conductors together into harnesses.A number of different types of protective coverings have been used, fromrelatively simple harness coverings, such as engineered tape, woventhreading, nylon braiding, asphaltic loom material etc., used to bundleconductors together, to more complicated harness coverings, such asextruded plastic and metal sleeving/conduits. Overmolded polymers (inwhich a polymer is molded to wholly or partially encase the wireharness) are especially desirable for use as harness coverings becausethey provide advantages that are not available from the use of othertypes of harness coverings. For example, in addition to controlling andmanaging the routing of numerous conductors, overmolded polymers provideprotection from damage to the bundled conductors that might otherwiseresult from salt corrosion, heat, vibration, water, and ultravioletradiation.

These overmolded polymers must be shaped in accordance with apredetermined three-dimensional geometry, in order to fit properly in avehicle. In the automotive and commercial vehicle industries, theovermolded polymer acts as a structural template for routing conductorsand electronic devices through the desired parts of the vehicle. Spacingand volume considerations and potential paths between electricalsubsystems are taken into account in determining the desiredthree-dimensional geometry for the harness coverings.

In order to create these overmolded harness coverings in acost-effective manner, these coverings are often formed pursuant toinjection molding. The mold generally includes two halves, i.e., abottom half and a top half, defining a cavity therebetween thatcorresponds to a desired shape, and therefore, the exact configurationof the mold is important. One conventional injection molding techniqueis reaction injection molding (RIM). In accordance with this technique,two liquid components, generally a polyol and an isocyanate, areinjected under pressure into the mold corresponding to the predeterminedthree-dimensional geometry of the harness covering. The liquidschemically react in the mold, i.e., the molecules of the componentscross-link, to form a solid thermoset polymer, generally polyurethane.

The molds used in injection molding are often relatively expensive tomanufacture. Generally, they are used to mass produce a high volume ofidentical parts and are less economical in low volume situations. Manymolds are made of steel or aluminum to ensure a relatively long moldlifespan, but these materials may be relatively expensive and add to thecost of injection molding. Further, in the case of commercial vehicles,molds must be relatively large for the formation of large harnesses,which again adds to the cost of injection molding.

In addition, complex geometries often involve the use of molds havingcomplex shapes, which further adds to the cost of molding. Athree-dimensional mold is very expensive, and to create thethree-dimensional geometries needed for the final harness coveringshape, the mold becomes very complicated and costly to construct.Typically, the use of “actions,” such as inserts or slides, in the moldallows a complex shape to be molded and, after molding, for the moldhalves to be separated. The use of “actions: generally increase thefabrication cost of a harness covering by increasing the amount andcomplexity of the mechanisms that need to be placed in the mold and byincreasing the molding time.

After the two liquids are injected and mixed, the resulting mixturecures over time to form a strong protective covering that is relativelystrong and lightweight. Generally, the covering cures sufficiently suchthat within a few minutes the harness can be removed from the mold,i.e., demolded, and handled without damage. The covering continues tocure over the next few hours and becomes increasingly rigid and solid.After curing is completed, the harness with covering is a rigid andgeometrically stable structure.

A need exists for a less expensive system and method for forming aharness having a predetermined three-dimensional geometry. There is alsoa need for a system and method for forming a harness covering that doesnot require the use of a separate three-dimensional mold for eachdesired three-dimensional geometry and that avoids the need forexpensive molds to form complex geometries. Further, there is a need foran economical system and method for forming large harness coveringhaving a desired geometry through reaction injection molding for use incommercial vehicles.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a wire harness and a bottom half of amold embodying features of the present invention;

FIG. 2 is a perspective view of the wire harness disposed in the bottomhalf of the mold of FIG. 1;

FIG. 3 is a perspective view of a top half of a mold and the wireharness and the bottom half of the mold of FIG. 1;

FIG. 4 is a perspective view of the wire harness disposed in the bottomhalf of the mold of FIG. 1 after injection molding;

FIG. 5 is a perspective view of the overmolded wire harness and thebottom half of the mold of FIG. 4;

FIG. 6 is a perspective view of a post-molding fixture and theovermolded wire harness of FIG. 4;

FIG. 7 is a perspective view of the overmolded wire harness disposed inthe post-molding fixture of FIG. 6;

FIG. 8 is a perspective view of the overmolded wire harness shown inFIG. 7 disposed into a harness having a three-dimensional geometry;

FIG. 9 is a perspective view of a second embodiment of an overmoldedharness illustrating features of the present invention;

FIG. 10 is a perspective view of the overmolded harness of FIG. 9disposed in a second embodiment of a post-molding fixture;

FIG. 11 is a perspective view of the overmolded harness of FIG. 9 afterremoval from the post-molding fixture of FIG. 10;

FIG. 12 is a perspective view of the overmolded harness of FIG. 9disposed in a third embodiment of a post-molding fixture;

FIG. 13 is a perspective view of the overmolded harness of FIG. 9 afterremoval from the post-molding fixture of FIG. 12; and

FIG. 14 is a perspective view of a fourth embodiment of a post-moldingfixture.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Preferred embodiments of the system and method of the present inventionare shown generally in FIGS. 1-8. As discussed further below, the systemand method make use of a mold 10 and post-molding fixture 12. In a firstphase, the mold 10 is used during an injection molding process,preferably a reaction injection molding process, to form a substantiallyflat harness 14 with covering 33 and having an intermediate, almosttwo-dimensional shape. In a second phase, the post-molding fixture 12 isused after the injection molding process to orient the harness 14 withcovering 33 to a predetermined three-dimensional geometry correspondingto the desire final shape.

The first phase involves injection molding to form a substantially flatand temporary geometry. A mold 10 used in a preferred embodiment can beseen in FIGS. 1-3. As can be seen in FIGS. 1 and 2, a bottom half 18 ofthe mold 10 is substantially rectangular in cross-section and includes acavity portion 20 formed in its interior surface 22. The harness 14interconnects a first electronic connector 26 for connection to a firstelectrical system and a second electronic connector 28 for connection toa second electrical system. The cavity 20 preferably includes aplurality of sub-cavities 30 that correspond generally to the shape ofthe harness 14 and that are filled when the reaction injection moldingprocess is initiated to form a covering 33. One or more of thesub-cavities 30 may also correspond to the shape of an electronicconnector or other device, such as the substantially rectangularsub-cavity 32 shown in FIGS. 1 and 2 corresponding generally to theshape of the first electronic connector 26.

The mold 10 used in the preferred embodiment makes use of sub-cavities30 in order to form a covering 33 that is corrugated. It has been foundthat these subcavities 30 are effective in centering the wire harness 14in the mold 10 such that the injection molding liquid can envelop theharness 14. Without the sub-cavities 30, the wire harness 14 may settlein the bottom of the cavity 20 such that the bottom of the harness 14 isnot properly encased during the injection molding process.Alternatively, for molds having a cavity 20 with a curvilinear section,portions of the harness 14 disposed in these curvilinear sections maynot be properly enveloped during injection molding without thesesub-cavities 30. The dimensions of the sub-cavities 30 may also bedesigned such that the corrugated covering 33 has a desired thickness.

The bottom half 18 of the mold 10 also includes leader pins 34 that maybe inserted into corresponding holes 36 in the top half 38 of the mold10 for alignment of the bottom half 18 with the top half 38. In thepreferred form shown in FIGS. 1 and 2, the bottom half 18 includes fourpins 34 positioned near the corners of the bottom mold half 18. The pins34 are inserted into the holes 36 in the top half 38 to ensure properalignment of the two mold halves 18 and 38 with one another during theinjection molding process. Although pins 34 and holes 36 are used in thepreferred embodiment for aligning the two mold halves 18 and 38 to oneanother, it should be evident that many other conventional types andshapes of alignment mechanisms, such as interlocking teeth, grooves,slots, channels, etc., may be used to align the mold halves 18 and 38with one another.

The cavity 20 in the bottom half 18 is preferably shaped to allow thecreation of a substantially two-dimensional intermediate form. As usedin a preferred embodiment shown in FIGS. 1 and 2, the interior surface22 of the bottom half 18 includes several raised portions 40 that areelevated above a lower portion 42. As should be evident, manyalternative interior surface, cavity, and sub-cavity shapes areavailable for the bottom half 18 of the mold 10. For example, in analternative form, the entire interior surface 22 of the bottom half 18may be a flat lower portion 42 and may not include any raised portions40. The interior surface 22 and cavity 20 preferably define anon-complex, relatively two-dimensional shape such that the mold 10 isrelatively inexpensive to create, can be reused many times, and can beused to create a standardized, intermediate harness form that may bemanipulated into any of a variety of complex three dimensionalgeometries.

The bottom half 18 of the mold also preferably includes a fill groove44. During injection molding, the liquid components are injected intothe mold 10 via the fill groove 44, which is in fluid communication withsub-cavities 30 of the mold 10. The mixture of liquid components flowsfrom the fill groove 44 to the sub-cavities 30 where they subsequentlyenvelop the wire harness 14 and, as discussed further below, cure toform a rigid protective covering about the harness 14.

A preferred form of a top half 38 of the mold 10 is shown in FIG. 3. Itpreferably includes indentations 46 corresponding to the raised portions40 of the bottom half 18 and for disposition of the harness 14. It mayalso include sub-cavities, similar to those described with respect tothe bottom half 18 of the mold 10. The top half 38 also preferablyincludes a mounting portion 48 for mounting and connecting the top half38 to a mixing head 50 of an injection molding system. During operation,as described further below, the mixing head 50 dispenses an injectionmolding fluid through a port 50 and through the fill groove 44 of themold 10.

As should be evident, any of a variety of molds 10 with top and bottomhalves 18 and 38 defining various shapes of cavities 20 and indentations46 can be used. The top and bottom halves are generally two portionsthat sealingly engage one another to form the mold 10. The interiorsurfaces of the top and bottom halves 18 and 38 generally define inversesurfaces with respect to one another. In one preferred form, one halfcontains sub-cavities 30 that are filled with liquid during theinjection molding process, while the other half does not containsub-cavities. In alternative forms, both halves may have sub-cavities 30that are filled during the injection molding process. Further, in otheralternative forms, the mold 10 may be composed of more than two moldhalves and may use “actions.” It is preferable that the mold 10 used isrelatively inexpensive and re-usable because, as described below, it isused herein to create an intermediate partially-cured harness form, notthe final fully-cured geometric form.

Initially, as shown in FIG. 2, the wire harness 14 and electronicconnectors 26 and 28 are positioned in and about the bottom half 18 ofthe mold 10. Next, as shown in FIG. 3, the top half 38 of the mold 10 ispositioned so as to engage the bottom half 18 and to enclose the harness14 and electronic connectors 26 and 28 within and about the mold 10. Theleader pins 34 of the bottom half 18 are inserted into the correspondingleader pin holes 36 in the top half 38 for proper alignment of the topand bottom halves 18 and 38. The top half 38 and bottom half 18 arepreferably maintained in sealing engagement with one another to preventthe escape of injection molding fluid from the mold 10. An injectionmolding press preferably applies a clamping force to keep the moldhalves 18 and 38 sealingly engaged during the injection molding process.

Once the harness 14 and electronic connectors 26 and 28 are enclosedwithin and about the mold 10, they are preferably subjected to areaction injection mold (RIM) process. More specifically, two liquidcomponents, preferably a polyol and an isocyanate, are preferablydispensed from respective feed tanks at a predetermined rate throughsupply lines 54 and 56 to the mixing head 50. The delivery of thecomponents to the mixing head 50 is synchronized, or metered, to ensurea uniform chemical reaction. The liquid reactants are thoroughly mixedin the mixing head 50 by high velocity collision of the reactants underhigh pressure. From the mixing head 50, the liquid polyurethane mixtureis injected through a port 50 and into the mold fill groove 44 atrelatively low pressure. The liquid mixture undergoes an exothermicreaction in the mold 10 to form the polyurethane polymer.

The proportions of polyol and isocyanate may be formulated such that thepolyurethane polymer is formed within a range of stiffnesses when fullycured. They may be formulated to form either a flexible foam or a rigidsolid. Here, it is generally contemplated that the proportions of polyoland isocyanate are preferably formulated such that the polyurethaneforms a rigid solid when fully cured. It is also contemplated, however,that the teachings described herein may be applied to provide athree-dimensional geometric form for foams or flexible solids.

Further, although it is generally contemplated that polyurethane isformed as the protective covering, other materials may be used, such asother types of thermosetting plastics. In general thermosetting plasticsare polymers that irreversibly cure to form a strong material in whichmolecular bonds are cross-linked. Subsequent high temperature reheatingof the cured material results in decomposition of the material before amelting point is reached, and accordingly, a thermoset material cannotbe melted after it is cured. Generally, thermoset polymers are moredurable than thermoplastic polymers because of this three-dimensionalcross-linking of bonds and are well-suited to high temperatureapplications.

Accordingly, thermosetting polymers are generally preferred over othermaterials, such as thermoplastic polymers, because they are moreconducive to the automotive and commercial vehicle environment.Thermosetting polymers do not melt in this heated environment, which mayinvolve the spraying of hot oil and other liquids. In contrast,thermoplastics tend to melt at higher temperatures and they thereforegenerally provide a less desirable covering.

Although one reaction injection molding process has been describedabove, other such conventional processes may be used. Reaction injectionmolding is generally preferred because the low internal mold pressureassociated with this type of molding allows the use of relativelyinexpensive mold materials. Further, reaction injection molding isespecially useful in the commercial vehicle industry to economicallyproduce large and intricately-shaped parts. More specifically, the twoliquid components are generally much less viscous than liquidthermoplastic polymer used in non-reaction injection molding techniquesand less clamping force is required to hold the mold 10 together, whichmakes the production of large parts with complex geometry moreeconomical. Although reaction injection molding is the preferredtechnique used herein, it should be evident that other conventionalinjection molding techniques may be employed.

As shown in FIGS. 4 and 5, after injection molding is completed, thewire harness 14 is covered with polyurethane polymer at regionscorresponding to the sub-cavities 30 of the mold 10. The top and bottomhalves 18 and 38 of the mold 10 are disengaged to allow removal of theharness 14 from the mold 10. Immediately following injection molding,the harness covering 33 has been partially cured such that the harness14 is generally ready for demolding within a few minutes after injectionsuch that the harness 14 can be removed and handled without damage. Theharness 14 may be demolded in accordance with any conventional method ofdemolding, such as through the use of ejector pins, air ejection, orstripper plates. In accordance with the preferred method, thepolyurethane cures over a period of hours to form a rigid harnesscovering 33, and it must be removed from the mold 10 before it becomesinflexible and incapable of manipulation. As described further below,after the harness 14 is removed from the mold 10, it is manipulated intothe desired final three-dimensional geometry before it becomesirreversibly cured.

The second phase of the method of the preferred embodiment involves theuse of a post-molding fixture to create the desired three-dimensionalgeometry. Although most of the curing is generally accomplished within afew minutes after injection, i.e., on the order of 90% or 95%, theharness covering 33 is not fully cured. The remaining 5%-10%, or asimilar percentage, of curing is accomplished over the next few hours,up to a maximum of about 36 hours. Manipulation of the harness covering33 into its final three-dimensional form is accomplished during thistime period before the covering 33 becomes fully cured. It ispreferable, however, to position the harness 14 in the post-moldingfixture 12 within about one hour of injection molding because, as moretime passes between injection molding and insertion in the fixture 12,the harness covering 33 becomes incrementally harder to manipulate anddoes not hold the final desired shape as well after insertion into thefixture 12.

As shown in FIGS. 6-8, after the harness 14 is demolded, a post-moldingfixture 12 is used to perform the final geometry work. The post-moldingfixture 12 may be created from any of various inexpensive materials,such as wood, paper, fiberglass, composites, cardboard, metal etc. Theuse of a relatively inexpensive post-molding fixture 12, in combinationwith the simple mold 10 described above, allows for a significantsavings in tooling costs.

One preferred form of a post-molding fixture 12 that may be used isshown in FIGS. 6 and 7. The post-molding fixture 12 is a jig used forshaping wires, cables, harnesses, etc., and it operates to maintain theharness 14 in the desired three-dimensional orientation as the covering33 fully cures into its rigid form. The jig is a template and guide thathelps control the orientation of various arms of the harness 14 withrespect to one another. The jig helps the operator to create the sameharness geometry over and over again and may be repeatedly used toconvert numerous harnesses having a two-dimensional intermediategeometry to their final three-dimensional form.

As shown in FIGS. 6 and 7, in one form, the jig 12 includes asubstantially flat and sturdy base portion 58. With respect to thepreferred embodiment used in the figures, the base portion 58 issubstantially rectangular in cross-section but, as should be apparent,the base portion 58 may be any of various shapes. The base portion 58also may be made of any various materials, such as plastic, wood, metaletc. The base portion 58 preferably includes a plurality of pinreceiving holes 60 arranged in a predetermined orientation to allow therepeated insertion of guide pins 62 at different positions of the baseportion 58, as described further below, such that the same jig 12 may bereused for different three-dimensional geometries.

As shown in FIG. 6, a pattern, or blueprint 64, may be drawn, marked,scratched, or otherwise imprinted on the top surface 66 of the baseportion 58. Alternatively, a pattern may be created on a separatematerial such as paper, and affixed to the top of the base portion 58,or affixed to a surface underneath a transparent base. This pattern 64is a two-dimensional representation of the harness 14 in its final form.It is intended as an aid to manipulating the harness 14 into the desiredthree-dimensional geometry. The pattern 64 shown in FIG. 6 allows theharness 14 to be manipulated from a substantially two-dimensionalgeometry, shown in FIGS. 5 and 6, to a three-dimensional geometry, shownin FIGS. 7 and 8.

In a preferred form shown in FIG. 6, the jig 12 includes guide pins 62that are used to set the final three-dimensional geometry. The guidepins 62 are preferably inserted in the pin receiving holes 60 in thebase portion 58 and are disposed at predetermined positions about thebase portion 58 to properly orient various portions of the harness 14.The guide pins 62 are securely inserted or fixed to the base portion 58to resist movement when the harness 14 is initially disposed in the jig12.

In one preferred form, for example, the guide pins 62 may be pegs thatcan be removably inserted into receiving holes 60 in a board 58 having aregular or irregular grid of receiving holes 60. The receiving holes 60may be oriented in accordance with a predetermined pattern and spacingsuch that the pegs 62 may be removably inserted into holes in the board58 corresponding to the desired geometry. Alternatively, in anotherpreferred form, pins or nails may be driven into a board atpredetermined positions corresponding to the desired geometry. It shouldbe evident that the guide pins 62 may be any of various shapes andmaterials and that, similarly, the base portion 58 of the post-moldingfixture 12 may be any of various shapes and materials.

As discussed above, after injection molding and demolding, the harness14 is in an intermediate, substantially two-dimensional form. Theharness 14 is then preferably manipulated into its desiredthree-dimensional geometry and disposed in the post-molding fixture 12.As can be seen in FIGS. 7 and 8, the harness 14 has been bent about theguide pins 62 and contorted such that various portions of the harness 14are spatially oriented above or beneath other portions. Depending on thesize of the harness 14, the force required to contort the harnessportions, and other considerations, the harness 14 may be manipulatedmanually by an individual either by hand or through the use of anyconvenient hand tools.

Another preferred form of the post-molding fixture 70 is shown in FIGS.10-11. In this example, the fixture 70 is used to shape the overmoldedharness 72 shown in FIG. 9. The overmolded harness 72 is flatter thanthe harness 14 described above. Various types of inexpensive molds maybe used to form the intermediate stage overmolded harness with covering,but it is generally contemplated that the molds will be substantiallytwo-dimensional to reduce mold tooling costs.

As shown in FIG. 10, the post-molding fixture 70 generally includes abase 74, walls 76, 78, and 80 extending from the base 74, and a tab 82projecting from one of the walls 80. In this form, the base 74 is abrick-shaped, wooden block having a greater depth than the post-moldingfixture 12 described above. This greater depth allows one of the arms 84of the harness 72 to be extended downwardly in accordance with thepredetermined three-dimensional geometry.

Three thin walls 76, 78, and 80 project upwardly from the top surface 92of the base 74 to permit manipulation of the other three arms 86, 88,and 90 of the harness 72 into the predetermined geometry. One of theupstanding walls 76 is formed to allow one arm 86 to extend in apredetermined direction in the substantially two-dimensional plane ofthe overmolded harness 72. Another upstanding wall 78 forms asubstantially 90 degree angle with a radiused corner 94 to orientanother arm 88 to a desired curvilinear shape in the substantiallytwo-dimensional plane. Further, in the form shown in FIG. 10, a tab 82projects from the third upstanding wall 80 to orient the fourth arm 90of the harness 72. The tab 82 has a predetermined height and acurvilinear end 96, which allows the fourth arm 90 to extend upwardlyout of the substantially two-dimensional plane in a curvilinear manner.

Another alternative preferred form of a post-molding fixture 100 isshown in FIGS. 12-13. The fixture 100 includes a base 102, walls 104,106, 108, and 110, and a tab 112. In this form, the base 102 is woodenbut is more irregularly shaped than the previously-described embodimentwith several side surfaces. The base 102 has a wall 104 extending fromone side surface 114 to orient one of the arms 116 downwardly. The base102 also includes a curved wall 106 and two other walls 108 and 110projecting upwardly from the top surface 114 of the base 102. Theseupstanding walls 106, 108, and 110 orient the other three arms 118, 120,and 122 of the overmolded harness 72 in a manner similar to thatdescribed above for the previous embodiment but fashioned to create adifferent predetermined three-dimensional geometry. For variouspreferred embodiments, the portions of the harness are preferablyfastened to the post-molding fixture by straps, clamps, or otherconventional fastening mechanisms to orient the harness in the desiredconfiguration.

The above embodiments of the post-molding fixture 12 may beincorporated, in whole or in part, as part of a shipping container. Thiscapability illustrates another advantage of certain preferred forms ofthe post-molding fixture 12. After the harness 14 has been positionedwithin the post-molding fixture 12, it is not necessary that it beremoved within any specific time period, and it therefore may be leftwithin the fixture 12 until after shipping to a desired location.Accordingly, the fixture 12 may be fashioned so that it may be easilyand conveniently integrated into or function as a shipping container.

Other types of post-molding fixtures 12 may also be used. In analternative preferred form, if the desired final geometry is relativelysimple, one or more ties 130 (FIG. 14) may be fastened about variousportions of the harness to achieve the final geometry. For example, ifit is desired to simply convert a substantially two-dimensional linearharness to a substantially two-dimensional curvilinear harness, it maybe sufficient to use a single wire tie 130 having ends 132 and 134fastened together to hold two portions of the harness in thepredetermined curvilinear orientation until the harness is fully cured.The tie 130 may be any of various thin strips of material used forfastening and may be made of any of various suitable materials, such aswire, string, rubber, or the like. One or more ties 130 may also be usedin conjunction with preferred forms of post-molding fixtures 12, 70, and100 described above to achieve the final predetermined geometry.

Accordingly, preferred embodiments have been described herein for amethod and system for forming a wire harness covering according to apredetermined three-dimensional geometry. The method generally includesthe steps of providing an injection mold that is substantially flat inshape and that defines a cavity therein; positioning a wire harnesswithin the cavity of the mold; introducing an injection molding liquidinto the cavity of the mold to form a covering about the wire harness;removing the wire harness from the mold before the covering is fullycured; providing a post-molding fixture corresponding to the desiredpredetermined three-dimensional geometry for the wire harness withcovering; and positioning the wire harness with partially-cured coveringwithin the post-molding fixture in accordance with the desiredpredetermined three-dimensional geometry. The system generally includesa wire harness; a substantially flat injection mold for forming apartially-cured wire harness covering having an intermediate,substantially two-dimensional shape; and a post-molding fixtureincluding a base and guide members projecting from the base fororienting the partially-cured wire harness covering in accordance withthe predetermined three-dimensional geometry.

The above described method and system for creating a complexthree-dimensional harness are much less expensive than conventionallymaking this three-dimensional shape with complex molds. Conventionally,the design of the harness covering using complex molds has been limitedby the ability to extract a complex part after it has been molded.Further, in order to create some of the complex three-dimensionalshapes, complex three-part and four-part reaction injection moldingtools have been required or the use of multiple tools has been required,resulting in a significant increase in tooling costs and investments.These disadvantages are not present with less complex flat molds, andthe above method significantly reduces tooling costs by employing asimple, reusable substantially flat mold.

Cost savings arise primarily because the less complex flat molds can betooled for a fraction of the cost involved for tooling the more complexmolds that have been conventionally used. For certain molds, it has beenestimated that the mold tooling costs may be reduced on the order of50%. In other words, the cost for creating a substantiallytwo-dimensional mold is about half that for creating a more complex,three-dimensional mold. In one specific example involving a mold madeout of a composite aluminum filled epoxy, the estimatedthree-dimensional mold cost was about $75,000, while the estimatedtwo-dimensional mold cost was about $40,000.

The above described method and system result in an inexpensive coveringthat provides additional advantages over other types of coverings. Forexample, as addressed above, it creates a covering that providesimproved environmental performance; it does not melt at hightemperatures, as are prevalent in automotive and commercial vehicleenvironments. In addition, the resulting covering has higher bundledensity; lower space requirements, especially within the automotive orcommercial vehicle environment; lower weight; a more pleasing aestheticappearance; improved reliability and durability; the capability toeasily integrate accessories, such as sensors and other electroniccomponents; part-to-part consistency; and ease of installation fororiginal equipment manufacturers (OEMs). Thus, the resulting coveringprovides improved performance over other materials, including, forexample, circular plastic tubing made of thermoplastics that melts athigh temperatures; metal sleeving that is relatively expensive; andbraided asphaltic loom material that involves a messy fabricationprocess.

Further, although the method and system have been addressed with respectto automotive and commercial vehicle industries, it should be evidentthat the method and system are not limited to these industries. It iscontemplated that the above described method and system may be used inother industries involving coverings for protecting conductors and otherelectric components and for interconnecting electrical systems andsubsystems, especially where it is desirable to reduce the cost of themethod. For example, it is contemplated that the above method and systemmight also be used in the aviation industry, with other types ofvehicles, and for non-vehicle applications where it is desirable tocreate a protective wire harness covering.

The foregoing relates to preferred exemplary embodiments of theinvention. It is understood that other embodiments and variants arepossible which lie within the spirit and scope of the invention as setforth in the following claims.

1. A system that forms a wire harness covering according to apredetermined three-dimensional geometry, comprising: a wire harness; aninjection mold that includes two mold halves that define a cavitytherebetween and that is substantially flat in shape that forms apartially-cured wire harness covering having an intermediate,substantially two-dimensional shape; and a post-molding fixture thatorients the partially-cured wire harness covering in accordance with thepredetermined three-dimensional geometry, wherein the partially-curedwire harness covering is positioned in the post-molding fixture within afirst predetermined time after forming the partially-cured wire harnesscovering.
 2. The system of claim 1, wherein the cavity comprisessub-cavities that form a corrugated covering of a predeterminedthickness for the wire harness.
 3. The system of claim 1, wherein thepost-molding fixture comprises a base with a plurality of guide membersthat project from the base that orients the wire harness in accordancewith the predetermined three-dimensional geometry.
 4. The system ofclaim 3, wherein the plurality of guide members are pins.
 5. The systemof claim 4, wherein the pins are disposed in pin receiving holes in thebase.
 6. The system of claim 5, wherein a subset of the pin receivingholes are arranged about the base according to a predeterminedconfiguration.
 7. The system of claim 3, wherein the guide members arewalls.
 8. The system of claim 7, wherein the base has a top surface andthe walls are upstanding from the top surface.
 9. The system of claim 7,wherein at least one of the walls has a tab protruding from the at leastone wall.
 10. The system of claim 1, wherein the post-molding fixture ismade from one of wood, fiberglass, composite, metal, alloy, orcardboard.
 11. The system of claim 1 wherein the post-molding fixturecomprises a tie that engages two portions of the harness for holding theharness in a fixed position while the covering cures.
 12. A system thatforms a wire harness, comprising: a first mold portion and a second moldportion that define a cavity therebetween, each of the first moldportion and second mold portion is substantially flat in shape forforming a partially-cured wire harness covering having a substantiallytwo-dimensional shape; and a post-molding fixture that orients thepartially-cured wire harness covering in accordance with a predeterminedthree-dimensional geometry.
 13. The system of claim 12, wherein thecavity comprises sub-cavities that form a corrugated-like covering of apredetermined thickness that encapsulates the wire harness.
 14. Thesystem of claim 13, wherein a subset of the sub-cavities position thewire harness within each the first mold portion and the second moldportion.
 15. The system of claim 12, further comprising a plurality ofleader pins that facilitate alignment of the first mold portion with thesecond mold portion.
 16. The system of claim 12, further comprising oneof interlocking teeth, grooves, slots or channels that facilitatealignment of the first mold portion with the second mold portion.
 17. Asystem of forming a three-dimensional wire harness, comprising: a twopiece mold that defines a cavity therebetween, wherein a combination ofa polyol and an isocyanate facilitate a reaction injection molding (RIM)process to form a partially-cured wire harness covering having anintermediate shape; and a means for post-molding that orients thepartially-cured wire harness covering from the intermediate shape into apredetermined three-dimensional configuration.
 18. The system of claim17, further comprising means for corrugating the wire harness covering.19. The system of claim 17, wherein means for post-molding is a wood,fiberglass, composite, metal, alloy or cardboard fixture.
 20. The systemof claim 17, further comprising means for establishing a predeterminedcure time based at least in part upon the molding process in view ofthickness of the wire harness covering.